A stent, which is also generally called a lumen expanding device, is a medical device that is formed by performing a polishing process, such as magnetic polishing, on a stent base that is formed such that a tubular body, which is made of material having high expansive force and high restoring properties, is subjected to laser cutting so that incisions are made on a side circumference surface of the tubular body in order that expansive force is given in a radially outward direction and whereby the side circumference surface is formed into a bellows-like shape.
Such a stent is mounted in a compressed manner, for example, inside a catheter or on a balloon at the tip of a catheter so that a diameter of the stent becomes tapered. When the catheter reaches a constriction region in a blood vessel, the stent is pushed out from the tip of the catheter, expands together with the constriction region in the blood vessel due to the self-restoring property or by the balloon at the tip of the catheter, and remains placed at this region.
Meanwhile, the following method has been known as an example of the above-mentioned magnetic polishing method. For example, there is a method of manufacturing a stent by housing a stent base in a polishing container; causing magnetic particles, which are formed of a magnetic substance and sealed inside the polishing container, to flow along a circumferential direction of the stent base due to the action of magnetic poles arranged outside the polishing container; and supplying abrasive particles, which are formed of a non-magnetic substance, along an axial direction of the stent base from an external supply source, thereby polishing a surface of the stent base. According to the above method, it is possible to polish the surface of the stent base in a good state and to manufacture a stent with good surface smoothness (see, for example, Patent Literature 1).